1. Field of the Invention
The invention is directed to an apparatus for treating a patient (human or animal) with focussed shockwaves which includes a patient bed and a shockwave source, the shockwave source being adjustable relative to the patient bed the apparatus also including means for acoustically coupling shockwaves to the patient that converge in a focal region lying on the acoustic axis of the shockwave source.
2. Description of the Prior Art
Devices of the type described above are currently employed for non-invasive disintegration of calculi situated inside the body, for example, kidney stones or gall stones. Their use has also been proposed in conjunction with healing or treating other pathologies, for example in tumor therapy or in treating vessel diseases.
An apparatus of the type initially cited that serves for the non-invasive disintegration of calculi situated in the body of a life form is described in the publication of Dornier Medizintechnik, "Dornier Lithotripter MPL 9000". The position of the calculus to be disintegrated is identified with a locating means and the calculus is subsequently brought into the focal region of the shockwaves by adjusting the shockwave source and the patient bed relative to one another. Under the action of a sequence of shockwaves generated with the shockwave source, the calculus disintegrates into fine fragments that can be eliminated naturally. In order to be able to align the patient in the required way, the patient bed is pivotable around the horizontal axis that proceeds transversely relative to the longitudinal axis of the patient bed. Further, the shockwave source is isocentrically adjustable with reference to the focal region of the shockwaves, i.e. the shockwave source is adjustable on a section of a spherical shell whose center lies in the focal region.
Particularly when disintegrating gall stones, a problem arises that the stones continuously change their position under the action of the shockwaves. When this is the case, an attempt must be made to bring the patient into such an inclined position by adjusting the patient bed so that the stones assume a stable position under the influence of the force of gravity, and thus retain this position under the influence of the shockwaves as well. This can be inherently achieved in the known apparatus by pivoting the patient bed around the horizontal axis so that, corresponding to the requirement of the therapy, the patient is brought either into a position wherein his head lies lower than his feet or into a position wherein his feet lie lower than his head. However, dislocations of the patient bed and shockwave source relative to one another thereby occur such that the calculi are then no longer situated in the focal region of the shockwaves. It is thus necessary to again locate the calculi before continuing the treatment and, by adjusting the patient bed, to again align the patient such that the calculi are situated in the focal region.
Devices of the type initially described are also known include a locating means adjustable relative to the other apparatus components for locating of a therapeutically relevant region, for example, a calculus, to which the target area of the shockwave generator is aligned. A device of this type is described in the publication of the Philips Company, C. H. F. Mueller, Medizinisch-Technische Systeme, "MFL 5000--Der Urologische Arbeitsplatz fuer Diagnose und Therapie". The position of the therapeutically relevant region, i.e. of the calculus to be disintegrated, is identified with an x-ray locating means and the calculus is subsequently brought into the focal region of the shockwaves by adjusting the patient bed relative to the shockwave source and relative to the locating means. Under the action of a sequence of shockwaves generated with the shockwave source, the calculus disintegrates into fine fragments that can be eliminated naturally. In the case of the known apparatus, the x-ray locating means includes an x-ray radiator and a radiation receiver in the form of an x-ray image intensifier that are attached to opposite ends of a U-shaped arc that is in turn attached to a stand pivotable around a horizontal axis. The intersection of the central ray of the x-ray locating means with the horizontal axis corresponds to the position of the focal region of the shockwaves. The shockwave source is pivotably attached such to an axis inclined relative to the vertical that proceeds through the intersection of the central ray with the horizontal axis that its central ray always proceeds through the said intersection and its focal region assumes the said position. In order to be able to align the patient in the required way, the patient bed, among other things, is pivotable around a further horizontal axis that proceeds transversely relative to the longitudinal axis of the patient bed.
As already explained, an attempt may potentially have to be made, particularly when disintegrating gall stones, to bring the patient into such an inclined position by adjusting the patient bed that the calculi assume a stable position under the influence of the force of gravity, retaining this stable position under the influence of the shockwaves as well. This can be achieved by pivoting the patient bed around the further horizontal axis in that the patient is brought into a position with elevated feet or, respectively, elevated pelvis. As described above, displacements of the patient bed relative to the shockwave source and relative to the x-ray location means occur so that the calculi are no longer situated in the focal region of the shockwaves. It is thus necessary to again locate the calculi before continuing the treatment and to align the patient such that the calculi are again situated in the focal region of the shockwaves.